Will execute the script i_love_cron.sh at five minute intervals from 9 AM to 5 PM (excluding 5 PM itself) every weekday (Mon-Fri) of every month except during the summer (June, July, and August).

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The cron daemon parses a configuration file known as crontab. Each user on the system can maintain a separate crontab file to schedule commands individually. The root user's crontab is used to schedule system-wide tasks (though users may opt to use /etc/crontab or the /etc/cron.d directory, depending on which cron implementation they choose).

There are slight differences between the crontab formats of the different cron daemons. The default root crontab for dcron looks like this:

Cronwhip

Anacron

Fcron

(Community, forum thread): Like anacron, fcron assumes the computer is not always running and, unlike anacron, it can schedule events at intervals shorter than a single day. Like cronwhip, it can run jobs that should have been run during the computer's downtime.